Modern aircraft contain visual display systems that provide pilots and/or flight crews with substantial amounts of important navigation, operational and situational awareness information, including information about the environment and terrain outside the aircraft. In fact, multi-functional aircraft displays can provide flight crews with computer-enhanced or generated, three-dimensional perspective images of terrain which may be especially important during conditions of low visibility. These images can include three-dimensional background and terrain information as well as graphics that represent pitch reference lines, airspeed, flight path information, altitude, attitude, and the like. In some implementations, the terrain imagery of the background can be high resolution, computer-generated terrain image data derived from databases and/or onboard vision sensor systems.
The designers of display systems are continually attempting to provide more realistic and useful displays. One problem with many computer generated displays is that the visual perspective is relatively fixed. In other words, the direction and angle of the perspective displayed on the visual display is generally straight ahead, i.e., at a fixed angle to the aircraft that does not change. While this is acceptable for most flying conditions, it may cause issues in some situations in which navigation and flight information is desired to be displayed relative to the background or terrain information. Such situations include take-off and landing of a helicopter, when the direction of intended flight during take-off is generally almost straight up or down, i.e., at a steep ascent or decent angle. In such cases, the flight path information cannot typically be accurately displayed relative to the background on the limited dimensions of the display, which generally shows a straight ahead view. In this situation, such a display would only show a limited portion of ground and forward field of view information ahead of the helicopter. Essentially, the flight path is “off the screen” of the visual display relative to the background in this instance, and the visual display may provide merely general guidance of the flight plan or no flight path information at all.
U.S. Pat. No. 8,339,284 discloses a lateral and vertical hybrid centering mode which shifts the display perspective view centering position based on the current flight path information of rotorcraft. This approach ensures that flight path information is useful for typical rotorcraft operations with its significantly wider range of path movement in comparison to the fixed wing aircrafts. The lateral and vertical centering mode is reactive to the flight path conditions, and display centering mode is automatically adjusted based on these conditions. However, in certain aggressive flight conditions, it may be desirable to provide a display that is less reactive to current flight path conditions.
Accordingly, it is desirable to provide improved visual display systems and methods. Furthermore, other desirable features and characteristics of the exemplary embodiments will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.